New Brain Scan Technique May Predict Alzheimer's Before Symptoms Appear

Scientists have developed a revolutionary brain imaging technique to observe a previously unseen pulse in the brain's smallest blood vessels. This discovery shows that these pulses change with age & could be an early indicator of Alzheimer’s disease.

Scientists have uncovered a hidden rhythm in the brain that may help identify early signs of Alzheimer’s disease and other age-related brain disorders. A team at the Mark and Mary Stevens Neuroimaging and Informatics Institute (Stevens INI) at the Keck School of Medicine, University of Southern California (USC), has created a revolutionary brain imaging technique.

This method reveals how the smallest blood vessels in the brain gently pulse with each heartbeat, a phenomenon that has never been observed in living humans before. Their findings, published in Nature Cardiovascular Research, provide a new approach to studying how these tiny vessels change as we age and how these changes might impact brain health.

This technique could potentially enable doctors to detect dementia at an earlier stage.

A Closer Look at the Brain’s Smallest Blood Vessels

The brain depends on tiny blood vessels to deliver oxygen and nutrients, as well as to remove waste products. With each heartbeat, these vessels expand and contract slightly, a process known as microvascular volumetric pulsatility.

Until recently, these movements were too subtle to detect without invasive methods, typically used in animal research. However, by utilizing an extremely powerful 7T MRI scanner and combining two advanced techniques (VASO and ASL), the USC team was able to safely measure these tiny pulses in human subjects.

They found that the pulsing of these small vessels becomes more pronounced as we age, particularly in deep white matter, which is responsible for connecting different parts of the brain. This area is essential for thinking, memory, and attention, yet it is also highly susceptible to reduced blood flow.

What This Means for Ageing and Alzheimer’s

Researchers already know that stiff or overactive large blood vessels can increase the risk of stroke, dementia, and damage to small vessels in the brain. This study fills a gap by showing how changes in the tiniest vessels might also play a significant role.

Older adults in the study showed stronger pulses in these microvessels, and those with high blood pressure exhibited even greater changes. This could disrupt the brain’s waste removal system, known as the glymphatic system, which helps eliminate harmful substances like beta-amyloid, a protein that accumulates in Alzheimer’s disease.

A New Tool for Early Detection?

Dr Arthur Toga, director of the Stevens INI, states that this method could transform how we understand and treat brain diseases.

"Being able to measure these tiny vascular pulses in vivo is a critical step forward. This technology not only advances our understanding of brain aging but also holds promise for early diagnosis and monitoring of neurodegenerative disorders."

The team is now exploring how this technique could be applied on more commonly available MRI machines in hospitals, such as 3T scanners. Future research will investigate whether measuring these vessel pulses could predict memory decline and serve as an early warning for dementia. Dr Wang believes that this method might help prevent and treat conditions like Alzheimer’s and millions of people could benefit from it.